Combinations of zinc pyrithione and cuprous oxide are known to be excellent antifouling agents when formulated into paints and paint bases (i.e., the paint before pigment addition), as disclosed, for example, in co-pending U.S. application Ser. No. 07/518,602. Unfortunately, however, such paints have now been found to thicken or gel unacceptably within a few days, at best, or a few hours, at worst, when formulated with typical commercial grades of zinc pyrithione in combination with cuprous oxide.
Heretofore, the solution to the problem of gellation of paints containing zinc pyrithione in combination with cuprous oxide has not been known to the knowledge of the present inventors. A solution to the problem would be highly desired by the paint manufacturing community since this combination of biocides provides excellent biocidal activity.